The investigators propose a novel technology to be used at the bedside or in the field: an FDA approved diagnostic skin patch which harvests, concentrates, and stabilizes a panel of protein fragments derived from skin transudate or sweat. While drug delivery patches are routinely used, the technology proposed here has exactly the opposite function: the harvesting of diagnostic markers using novel affinity bait nanoparticles, bound within an adhesive skin patch. The proposed technology may overcome all major physiological barriers that have prevented the use of this biologic fluid for diagnostic testing. Sweat disease protein fragments are subject to rapid degradation due to proteases present in sweat and normal skin bacterial flora, and exist in extremely low abundance, far below the detection sensitivity of standard analysis platforms. Harvesting hydrogel nanoparticles are engineered with chemical high affinity baits so that they sequester the low abundance target analytes, and protect them from degradation indefinitely. Once applied to the skin, the nanoparticles in the patch harvest minute by minute, and protect from degradation, all candidate analytes in the sweat underneath the patch. The core shell bait nanoparticles are a completely novel technology that can amplify the sensitivity of protein fragment detection by 100 fold. No other technology exists that has a similar yield, concentration ability, and stabilization function. Once the collection is complete, the patch will be mailed to the diagnostic lab at room temperature. Upon receipt, the nanoparticle-captured analytes of interest can be eluted from the patch for routine measurement using any platform. Feasibility studies have demonstrated virtually 100 percent capture and 100 percent elution yield of low abundance interleukins in model sweat solutions. The investigators will collect sweat from healthy volunteers under Institutional Review Board approval. Mass spectrometry will be used to discover novel sweat protein fragments that have been concentrated and preserved in the patch. Low abundance labile protein fragments harvested from the nanoparticles will be measured by clinical immunoassays to verify sensitivity and precision. Data gathered from this study will be used to develop a foundation for sweat protein fragment testing of cutaneous disease.